IDLE screw "normal idle" question and IAC Valve

terranaj98 · Post by **terranaj98** » Tue Jun 05, 2007 6:58 am

So whats the normal idle RPM's for a 1990 legacy LS wagon?
i cleaned the throttle body and we fiddled with the screw on the top of the engine that fits a slothead screwdriver
it went from high idle 1500rpm to 1000rpm (current)
trying to fine the norm..
please advise..

also im trying to get the stupid IAC valve off.. but theres so much crap to move before i can reach it..
oh yea.. i lost one of the screws that holds a electronic plug on..
that ticked me off hopefully the dealer wont charge me much

does anyone know a homedepot alternative?

im going to open a discussion on tailgate part replacement.

since i used a lot of homedepot parts to replace the tailgate rusted out bolted parts

PM me if your interested in the pictures and discussion

grippingdrifting · Post by **grippingdrifting** » Tue Jun 05, 2007 11:18 am

According to the owner's manual, idling speed should be 600-800 RPMs. There should be a link to an owner's manul scan in a post under the stuff you need to know forum (along with a bunch of other service manual scans).

If you have an N/A the IAC valve should only be held on by 3 bolts: two on top & one on bottom towards front of engine. The big hose coming off the center is for air so can be removed but the 2 small hoses on the sides are coolant lines so make sure to drain some coolant before removing. You can also remove the hoses that run to the PCV valve.

What plug did you lose the screw for?

Post by **Legacy777** » Tue Jun 05, 2007 5:22 pm

Are you talking about this bypass screw?
http://www.main.experiencetherave.com:8 ... images/tb/

You really shouldn't have cleaned your TB. That black goo is a sealant, and not carbon. It's supposed to be there.

If that needle valve/screw is what you were adjusting, crank it down all the way, and let the IAC valve do what it's supposed to do.

There are 4 bolts for the IAC valve, not 3. You don't really need to drain the coolant....a little will spill out, but it's not too big a deal.

As for your missing screw....just find one that is metric and will fit. Also, if you remove the electro magnet portion of the IAC make sure you mark it's orientation and put it back exactly where it was.

terranaj98 · Post by **terranaj98** » Tue Jun 05, 2007 8:26 pm

the black electronic connector thats "BLACK"
in this photo

terranaj98 · Post by **terranaj98** » Tue Jun 05, 2007 9:55 pm

hahaha found it.. in the daylight..
thank god..
it only costs.. 17cents for a new one though
buying 4.. special order though
ummm
the idle is connected to the transmission shifting i believe
considering if i tuned up the revs the transmission finds the next gear better...
if the revs are lower the transmission searches and finds it not immediately.. but 6 seconds or less..

i really want to take my IAC valve out.. and clean it. but.. the darn thing is.. like in a corner and barricaded itself with hoses and annoying stuff so.. ill wait on that..

grippingdrifting · Post by **grippingdrifting** » Tue Jun 05, 2007 11:28 pm

The black connector on the upper right is the throttle position sensor and you don't want to touch that. There should be paint alignment marks so make sure it lines up properly.

You can clean the IAC without removing it. Do a search and you should be able to find directions.

Legacy777 wrote:There are 4 bolts for the IAC valve, not 3.

That's weird, I only have 3 bolts on mine. There is a fourth bolt hole on my IAC valve but there isn't anything behind it to screw into.

terranaj98 · Post by **terranaj98** » Tue Jun 05, 2007 11:33 pm

thanks buddy..
hopefully it isnt hard..

ok.. well i think i touched the TPS.. sensor..
but.. i see the paint your talking about and its about lined up.. so.. no harm no foul.. HOPEFULLY:p

Post by **Legacy777** » Wed Jun 06, 2007 4:46 pm

terranaj98 wrote:hahaha found it.. in the daylight..
thank god..
it only costs.. 17cents for a new one though
buying 4.. special order though
ummm
the idle is connected to the transmission shifting i believe
considering if i tuned up the revs the transmission finds the next gear better...
if the revs are lower the transmission searches and finds it not immediately.. but 6 seconds or less..

i really want to take my IAC valve out.. and clean it. but.. the darn thing is.. like in a corner and barricaded itself with hoses and annoying stuff so.. ill wait on that..

All the transmission control is computer controlled....adjusting the idle should not really affect how the transmission shifts.

What did you do to the TPS sensor?

terranaj98 · Post by **terranaj98** » Wed Jun 06, 2007 5:57 pm

nothing.. i could of knocked it with the intake cleaner..

Post by **Legacy777** » Wed Jun 06, 2007 6:09 pm

Ok....so you didn't adjust it at all. That was what I was trying to determine.

terranaj98 · Post by **terranaj98** » Wed Jun 06, 2007 8:20 pm

yea...

terranaj98 · Post by **terranaj98** » Thu Jun 07, 2007 12:18 am

josh.. found the problem and you were spot on..
i just didnt believe it till it was fixed..
Yes we did touch the TPS sensor.. we moved it like 1/8 1/10th off the normal painted line.. i think my mechanic unloosened the screws.. and moved it and bam..
2x less shaking
2x less headaches
2x BETTER idle
2x BETTER air/fuel ratio
2x BETTER SHIFTING!

thanks for ur help josh

your #1

Post by **Legacy777** » Thu Jun 07, 2007 3:45 pm

You can adjust the TPS, and this is how you do it.

http://www.main.experiencetherave.com:8 ... sting3.jpg

I'd recommend you or your mechanic check the TPS per the scan since it was moved.

Glad you got it figured out though.

terranaj98 · Post by **terranaj98** » Thu Jun 07, 2007 9:07 pm

no thanks..
now that its running like a pro..
im leaving it.. till something needs changing..
like spark plugs wires.. cap rotor.. something simple..
this was simple but a bad mistake on my part

thanks josh again

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IDLE screw "normal idle" question and IAC Valve

IDLE screw "normal idle" question and IAC Valve